Non-full-phase protection loop, latch-up protection circuit and non-full-phase protection method

Abstract

The invention discloses an open-phase protection loop, a latch-up protection circuit and an open-phase protection method, and the open-phase protection loop comprises a main circuit which inputs three-phase power; the three-phase state circuit is connected to the main circuit and is used for detecting a three-phase state; and the relay protector is connected with the three-phase state circuit and is used for sending out an alarm signal. According to the non-full-phase protection loop, three-phase inconsistency is converted into loop energization (the loop is disconnected when the states are consistent and the loop is connected when the states are inconsistent) by utilizing the normally-closed switch and the normally-open switch which are arranged at each phase, so that whether the three-phase protection loop is in a three-phase inconsistent state can be judged. And the time delay relay and the non-full-phase intermediate relay are arranged, and the time delay function of the time delay relay is utilized to filter instantaneous abnormity, so that protection is triggered only when three phases continuously exist and are inconsistent, and the reliability is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of circuit breaker protection, in particular to a non-phase fault protection circuit, a blocking protection circuit and a non-phase fault protection method. BACKGROUND

[0002] Three-phase inconsistency refers to that in a three-phase power system, three phases (A phase, B phase and C phase) of a three-phase circuit breaker fail to correctly act according to instructions when they should act simultaneously (such as simultaneously open or simultaneously close), resulting in that the three phases of the three-phase circuit breaker are in different states (for example, one phase is open while the other two phases are not open, or one phase is closed while the other two phases are not closed, etc.).

[0003] The prior art usually adopts a phase-splitting circuit breaker, and the non-phase fault protection of the prior art mainly relies on the following schemes: mechanical three-phase linkage detection, which detects the opening and closing states of the three-phase circuit breaker through a mechanical linkage mechanism and triggers protection when the mechanical positions are inconsistent; electrical quantity criterion detection, which collects three-phase currents or voltages and judges the non-phase fault state based on three-phase unbalance degree (such as zero-sequence current or negative-sequence current); and auxiliary contact direct monitoring, which judges the opening and closing positions by using a single normally open or normally closed contact state of an auxiliary switch of the circuit breaker and discriminates inconsistency through three-phase parallel logic.

[0004] However, the prior art has different limitations. Limitations of mechanical detection: mechanical components are prone to wear and tear, jamming and low reliability; slow response speed, which cannot capture transient non-phase fault in time. Limitations of electrical quantity criterion: may lead to misjudgment (such as zero-sequence current misoperation) when the system is lightly loaded or the load is unbalanced; needs to be configured with a current transformer (CT) / voltage transformer (PT), which increases cost and complexity. Limitations of auxiliary contact monitoring: only relies on a single normally open or normally closed contact, which has the risk of misjudgment caused by contact sticking and poor contact; no time delay filtering mechanism is set, which is easily disturbed by the transient process of closing / opening (such as circuit breaker bounce). SUMMARY

[0005] In view of the problems of easy failure and false alarm of the existing non-phase fault protection, the present application is proposed.

[0006] Therefore, the present application aims to provide a non-phase fault protection circuit, which aims to capture non-phase fault in time and reduce false alarm.

[0007] To solve the above technical problems, the application provides the following technical scheme: a main circuit is used for inputting three-phase electricity; a three-phase state circuit is connected to the main circuit and is used for detecting three-phase state; a relay protection is connected to the three-phase state circuit and is used for sending an alarm signal; wherein the three-phase state circuit comprises three single-phase circuits, a normally closed switch and a normally open switch are arranged on each single-phase circuit, a connecting contact is arranged between the normally closed switch and the normally open switch of each single-phase circuit, each connecting contact is connected to each other, and the output ends of each single-phase circuit are combined into one output.

[0008] As a preferred scheme of the non-phaseless protection circuit, the output end of the three-phase state circuit is connected with a connecting piece, one end of the connecting piece is connected with the output end of the three-phase state circuit, and the other end is connected with the relay protection.

[0009] As a preferred scheme of the non-phaseless protection circuit, the relay protection comprises a main circuit connected with the three-phase state circuit and a bypass connected in parallel with the main circuit.

[0010] As a preferred scheme of the non-phaseless protection circuit, a time delay relay is arranged on the main circuit, a non-phaseless intermediate relay is arranged on the bypass, and a time delay contact of the time delay relay is further arranged in front of the non-phaseless intermediate relay.

[0011] As a preferred scheme of the non-phaseless protection circuit, the input end of the three-phase is connected in series with the output end of the relay protection in a closing circuit.

[0012] The application further provides a locking protection circuit, which aims to provide various closing and opening protection.

[0013] To solve the above technical problems, the application provides the following technical scheme: the non-phaseless protection circuit is connected in parallel with a closing locking circuit, an opening locking circuit and an SF6 low pressure locking circuit.

[0014] As a preferred scheme of the locking protection circuit, the closing locking circuit comprises three branches, a closing locking control switch is arranged on each branch, and a closing locking relay is connected to the output end of each closing locking control switch.

[0015] As a preferred scheme of the locking protection circuit, the opening locking circuit comprises three branches, an opening locking control switch is arranged on each branch, and an opening locking relay is connected to the output end of each opening locking control switch.

[0016] As a preferred scheme of the locking protection circuit, the SF6 low pressure locking loop comprises three branches, and each branch is provided with an SF6 gas density relay, and the output end of each SF6 gas density relay is connected with a low pressure locking relay.

[0017] The application further provides a non-phase protection method applied to the non-phase protection circuit, and the method comprises the following steps of: S1, collecting the action states of three-phase circuits respectively;

[0018] S2, judging inconsistency according to the action states of the three-phase circuits;

[0019] S3, performing time delay filtering on the action states of the three-phase circuits;

[0020] S4, performing protection on the action states of the three-phase circuits after time delay filtering.

[0021] The application has the following beneficial effects: the normally closed switch and the normally open switch arranged in each phase are used to convert the three-phase inconsistency into circuit energization (the circuit is disconnected when the states are consistent, and the circuit is connected when the states are inconsistent), so that whether the three-phase inconsistency state exists can be judged. Compared with the mechanical structure such as the mechanical connecting rod, mechanical failures such as wear do not occur, and the mechanical structure is not easy to be misoperated by the staff. Compared with the electrical quantity judgment, the electrical quantity judgment is not easy to be misoperated by the zero sequence current error, and the false alarm is reduced. Compared with the auxiliary contact monitoring mode, each phase is separately provided with a circuit, and the contact sticking or poor contact failure does not exist. And through the time delay relay and the non-phase intermediate relay, the time delay function of the time delay relay is used to filter the transient abnormality, so that only the persistent three-phase inconsistency triggers the protection, and the reliability is improved. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0023] Figure 1 It is a schematic diagram of a non-phase protection circuit of the application.

[0024] Figure 2 It is a schematic diagram of a non-phase protection circuit of the application in a circuit breaker.

[0025] Figure 3 It is a schematic diagram of a locking protection circuit of the application. DETAILED DESCRIPTION

[0026] In order to make the above objectives, features and advantages of the present application more apparent, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0027] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. The present application, however, can be practiced in a variety of ways beyond the specific embodiments described herein without departing from the scope of the present application, which is set forth with particularity in the claims. Implementations of the present application can be implemented using two or more specific embodiments together.

[0028] Second, the "one embodiment" or "an embodiment" as used in this specification means that a particular implementation can include a particular feature, structure, or characteristic. However, the appearance of "in one embodiment" or "in an embodiment" at different places in the specification does not necessarily mean that all embodiments include the particular feature, structure, or characteristic.

[0029] Third, the present application is described in connection with exemplary diagrams. In the description of the present application, the sectional view of the device structure is partially enlarged without the general proportion for the convenience of description, and the schematic diagram is only an example, which should not limit the scope of the present application. In addition, the three-dimensional spatial dimensions of length, width and depth should be included in the actual manufacture.

[0030] Embodiment 1

[0031] Referring to Figure 1 , Figure 2 , the first embodiment of the present application provides a non-full-phase protection circuit, which includes a main circuit inputting three-phase electricity, a three-phase state circuit 200 connected to the main circuit for detecting three-phase state, and a relay protection 400 connected to the three-phase state circuit 200 for sending an alarm signal. The three-phase state circuit 200 includes three single-phase circuits 201, each of which is provided with a normally closed switch 202 and a normally open switch 203. The normally closed switch 202 and the normally open switch 203 of each single-phase circuit 201 are provided with a connecting contact 204, and each connecting contact 204 is connected to each other. The output ends of each single-phase circuit 201 are combined into one output.

[0032] The non-full-phase protection circuit is connected to the positive power supply of the three-phase inconsistent protection outlet of the main and auxiliary tripping control circuit 800 of the circuit breaker body, which is used to ensure that the three-phase inconsistent protection will not malfunction.

[0033] The normally closed switch 202 and the normally open switch 203 are combined as auxiliary switches. The relay protection 400 comprises a main circuit 401 connected with the three-phase state circuit 200, a bypass 402 connected in parallel with the main circuit 401, a time delay relay 403 arranged on the main circuit 401, a non-full-phase intermediate relay 404 arranged on the bypass 402, and a delay contact 403a of the time delay relay 403 arranged in front of the non-full-phase intermediate relay 404. The output ends of the main circuit 401 and the bypass 402 are merged as a protection outlet 405.

[0034] The input ends of the three phases are connected in series with the output ends of the relay protection 400 in the closing circuit of the 330kV circuit breaker. The three-phase power input of the main power supply of the 330kV circuit breaker enters the main circuit, and the three-phase power input of the main circuit enters the three-phase state circuit 200 after which the A phase, the B phase and the C phase enter the respective single-phase circuits 201. After detection by the respective single-phase circuits 201, it is determined whether the three-phase actions are consistent, and then enters the relay protection 400. The relay protection 400 determines whether to close according to the three-phase actions and filters the misoperation.

[0035] When the three-phase states are consistent (all closing or all opening), the circuit is disconnected, and the protection does not act.

[0036] All the three phases are closed: the normally closed switch 202 is disconnected, the normally open switch 203 is closed, the normally closed switches 202 of the A phase, the B phase and the C phase are all disconnected, and the respective single-phase circuits 201 are not connected. At this time, the output node of the three-phase state circuit 200 has no voltage, the coil of the time delay relay 403 is not powered, and the time delay relay 403 and the non-full-phase intermediate relay 404 do not act.

[0037] All the three phases are opened: the normally closed switch 202 is closed, the normally open switch 203 is disconnected, the normally open switches 203 of the A phase, the B phase and the C phase are all disconnected, and the respective single-phase circuits 201 are not connected. At this time, the output node of the three-phase state circuit 200 has no voltage, the coil of the time delay relay 403 is not powered, and the time delay relay 403 and the non-full-phase intermediate relay 404 do not act.

[0038] Taking the A phase opening and the B phase and the C phase closing as an example, the normally closed switch 202 of the A phase (opening) is closed, and the normally open switch 203 is disconnected. At this time, the front half of the single-phase circuit of the A phase is connected, but the normally open switch 203 is disconnected, and the rear half of the single-phase circuit of the A phase is not connected. The normally closed switches 202 of the B phase and the C phase (closing) are disconnected, and the normally open switches 203 are closed. At this time, the front half of the single-phase circuit of the B phase and the C phase is connected, but the normally closed switches 202 are disconnected, and the front half of the single-phase circuit of the B phase and the C phase is not connected.

[0039] At this time, the intermediate connection contact 204 of the single-phase circuit 201 of phase A is closed by the normally closed switch 202 to connect the three-phase circuit 100, i.e. the power supply positive, the single-phase circuit 201 of phase B and C is connected to the intermediate connection contact 204 by the normally open switch 203 to form a path, the output node of the three-phase state circuit 200 obtains the power supply voltage, which is added to the coil of the time delay relay 403 through the connecting piece 300, the time delay relay 403 is energized, i.e. the three-phase inconsistent state.

[0040] After the coil of the time delay relay 403 is energized, the delay contact 403a thereof is closed after a set delay (for example, 0.5s, to avoid transient fault operation during closing), at this time, the coil of the non-full-phase intermediate relay 404 is energized, i.e. the three-phase inconsistent protection is executed to drive tripping or alarm, and the protection action is completed.

[0041] In use, three-phase electricity first enters the three-phase circuit 100, which divides the three-phase electricity into phases A, B and C, each of which enters a single-phase circuit 201, in which, according to the opening and closing actions of the circuit breaker as a whole, the normally closed switch 202 is closed and the normally open switch 203 is opened during opening, and the normally closed switch 202 is opened and the normally open switch 203 is closed during closing, at this time, phases A, B and C pass through the respective single-phase circuits 201, if the actions of the three single-phase circuits 201 are the same, the three-phase state circuit 200 does not trigger the relay protection 400, and the time delay relay 403 and the non-full-phase intermediate relay 404 are not energized, i.e. the three-phase state is consistent. If the action of one single-phase circuit 201 is inconsistent with that of the other two single-phase circuits 201, at this time, the three-phase state circuit 200 is turned on, and the power supply voltage can trigger the relay protection 400 from the three-phase circuit 100 through the three-phase state circuit 200 and the connecting piece 300, thereby triggering the time delay relay 403, after a preset delay, if it is still turned on, the delay contact 403a is closed to trigger the non-full-phase intermediate relay 404, i.e. the three-phase inconsistent protection is triggered.

[0042] Embodiment 2

[0043] Reference Figure 3 For the second embodiment of the present application, which is different from the first embodiment, a locking protection circuit is further provided, which comprises a non-full-phase protection circuit, a closing locking circuit 500, an opening locking circuit 600 and an SF6 low pressure locking circuit 700 connected in parallel with the non-full-phase protection circuit, the non-full-phase protection circuit, the closing locking circuit 500, the opening locking circuit 600 and the SF6 low pressure locking circuit 700 together constitute the locking protection circuit, to realize artificial forced closing / opening locking and simultaneous closing / opening locking in SF6 low pressure to force the equipment to stop and prevent fault expansion.

[0044] Wherein, the closing locking loop 500 includes three branches, and each branch is provided with a closing locking control switch 501, and the output end of each closing locking control switch 501 is connected with a closing locking relay 502. When the circuit breaker is placed in the "closing locking" position, the contact of the closing locking control switch 501 is closed (normally open); the contacts of the three-phase closing locking control switch 501 are in parallel, and the closing of any phase can trigger the loop. After the loop is triggered, the coil of the closing locking relay 502 is powered, the normally closed contact of the closing locking relay 502 is connected into the closing loop, and the closing power is cut off. As long as the closing locking control switch 501 of any phase is triggered to lock, the closing power can be cut off.

[0045] The opening locking loop 600 includes three branches, and each branch is provided with an opening locking control switch 601, and the output end of each opening locking control switch 601 is connected with an opening locking relay 602. When the circuit breaker is placed in the "opening locking" position, the contact of the opening locking control switch 601 is closed (normally open); the contacts of the three-phase opening locking control switch 601 are in parallel, and the closing of any phase can trigger the loop. After the loop is triggered, the coil of the opening locking relay 602 is powered, the normally closed contact of the opening locking relay 602 is connected into the opening loop, and the opening power is cut off. As long as the opening locking control switch 601 of any phase is triggered to lock, the opening power can be cut off.

[0046] The SF6 low pressure locking loop 700 includes three branches, and each branch is provided with an SF6 gas density relay 701, and the output end of each SF6 gas density relay 701 is connected with a low pressure locking relay 702.

[0047] The SF6 gas density relay 701 monitors the SF6 gas density, and the contact of the SF6 gas density relay 701 is disconnected in normal state and is closed in low pressure state; the contacts of the three-phase SF6 gas density relay 701 are in parallel, and the low pressure of any phase can pass the loop. At this time, the coil of the low pressure locking relay 702 is powered, and the normally closed contact of the low pressure locking relay 702 is connected into the closing loop and the opening loop at the same time, and the power of the two is cut off. At this time, the low pressure locking relay 702 simultaneously locks the closing and the opening, and forces the equipment to stop for maintenance, so that the accident is avoided to be expanded.

[0048] The remaining structure is the same as that of the structure of the first embodiment.

[0049] Embodiment 3

[0050] As the third embodiment of the present application, the embodiment provides a non-full-phase protection method, which includes the following steps: S1, respectively collecting the action states of a three-phase circuit 100; S2, judging inconsistency according to the action states of the three-phase circuit 100; S3, performing delay filtering on the action states of the three-phase circuit 100; S4, protecting the action states of the three-phase circuit 100 after delay filtering.

[0054] Further, S1.1, when the circuit breaker is closed, the normally open switch 203 is closed, and the normally closed switch 202 is opened; when the circuit breaker is opened, the normally closed switch 202 is closed, and the normally open switch 203 is opened.

[0055] In S2, by comparing the state combination of each normally open switch 203 and normally closed switch 202 of the three phases, if there is at least one phase whose switch state combination is different from the other phases (i.e., the three-phase closing and opening states are inconsistent), the coil power supply circuit of the time delay relay 403 is turned on.

[0056] In S3, after the coil of the time delay relay 403 is powered, the preset delay time is filtered to filter the transient state abnormality, the delay contact 403a is closed, and the coil power supply circuit of the non-full-phase intermediate relay 404 is turned on.

[0057] In S4, after the coil of the non-full-phase intermediate relay 404 is powered, the outlet action of the non-full-phase protection is triggered, and the outlet action includes at least one of circuit breaker tripping and alarm signal output.

[0058] It is important to note that the construction and arrangements of the application shown in the various exemplary embodiments are illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described in the application. For example, elements shown as integrally formed can be constructed of multiple parts or elements, the position of elements can be reversed or otherwise varied, and the nature or number of elements or positions can be altered or varied. Accordingly, all such variations are intended to be included within the scope of the application. The order or sequence of any process or method steps can be changed unless otherwise specified, and the omission of any step is also intended. Therefore, the application is not limited to the specific embodiments disclosed herein, but includes all such modifications and variations as fall within the scope of the appended claims.

[0059] Furthermore, in order to provide a concise description of exemplary embodiments, all features of an actual implementation can not be described (i.e., those unrelated to the presently contemplated best mode of carrying out the application, or those unrelated to enabling the claimed application).

[0060] It should be noted that the above examples are only used to illustrate the technical solutions of the present application but not limit the present application. Although the present application is described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or equivalently replaced, without departing from the spirit and scope of the technical solutions of the present application, which should be covered in the scope of the claims of the present application.

Claims

1. A phase failure protection circuit, characterized by: include, Main circuit, input three-phase power; A three-phase status circuit (200) is connected to the main circuit and is used to detect the three-phase status. A relay protection (400) is connected to the three-phase status circuit (200) and is used to issue an alarm signal; The three-phase state circuit (200) includes three single-phase circuits (201). Each single-phase circuit (201) is equipped with a normally closed switch (202) and a normally open switch (203). Each single-phase circuit (201) has a connecting contact (204) between the normally closed switch (202) and the normally open switch (203). The connecting contact (204) is connected to each other. The output terminals of each single-phase circuit (201) are combined into one output.

2. The phase-to-phase protection circuit of claim 1, wherein: The output terminal of the three-phase state circuit (200) is connected to a connecting piece (300). One end of the connecting piece (300) is connected to the output terminal of the three-phase state circuit (200), and the other end is connected to the relay protection (400).

3. The phase-to-phase protection circuit of claim 2, wherein: The relay protection (400) includes a main circuit (401) connected to the three-phase state circuit (200) and a bypass (402) connected in parallel with the main circuit (401).

4. The phase-to-phase protection circuit of claim 3, wherein: A time delay relay (403) is provided on the main circuit (401), and a non-full-phase intermediate relay (404) is provided on the bypass (402). A time delay contact (403a) of the time delay relay (403) is also provided in front of the non-full-phase intermediate relay (404).

5. The phase-to-phase protection circuit of claim 4, wherein: The input terminals of the three phases are connected in series with the output terminals of the relay protection (400) in the closing circuit.

6. A closed loop protection circuit comprising a non- solid state protection circuit according to claims 1-5, characterized in that: It also includes a closing interlocking circuit (500), a tripping interlocking circuit (600), and an SF6 low-pressure interlocking circuit (700) connected in parallel with the non-full-phase protection circuit.

7. The latch-up protection circuit of claim 6, wherein: The closing interlocking circuit (500) includes three branches, each of which is equipped with a closing interlocking control switch (501), and the output terminal of each closing interlocking control switch (501) is connected to a closing interlocking relay (502).

8. The latch-up protection circuit of claim 7, wherein: The tripping interlocking circuit (600) includes three branches, each of which is equipped with a tripping interlocking control switch (601), and the output terminal of each tripping interlocking control switch (601) is connected to a tripping interlocking relay (602).

9. The latch-up protection circuit of claim 9, wherein: The SF6 low-pressure interlocking circuit (700) includes three branches, each of which is equipped with an SF6 gas density relay (701), and the output terminal of each SF6 gas density relay (701) is connected to a low-pressure interlocking relay (702).

10. A method for phase failure protection, applied to the phase failure protection circuit of claims 1-5, characterized in that: Includes the following steps, S1. Collect the operating status of the three-phase circuit (100) respectively; S2. Make inconsistency judgments based on the operating state of the three-phase circuit (100); S3. Delay filtering is performed on the operating state of the three-phase circuit (100); S4. Protect the operating state of the three-phase circuit (100) after delay filtering.

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